.dingdan {
    height: 100vh;
    background: #f4f4f4;
    position: sticky;
    top:0;
    z-index: 99999;
}

.btn {
    width: 220px;
    height: 45px;
    line-height: 45px;
    background: #1c8ee7;
    border: none;
    font-size: 15px;
    color: #fff;
    border-radius: 13px;
}